This application describes my invention of a new extruded plastic window construction having openable panes.
In the prior art there have been many types of insulating windows manufactured for installation on existing window frames. These have included exterior mounted storm windows, usually aluminum, with glass panes framed in aluminum channels which ride on multiple tracks, and which may be opened or closed. Such multiple track windows may also include screens for use while a window is open.
As is well known, the typical exterior aluminum storm window is costly and includes many parts, including separate frame and sash members to hold the glazing or screening panels, top, side and sill rails, as well as tracked inside rails within which the framed window and screen panels slide.
In addition to conventional storm windows, plastic flim has been applied with tape or other webbing to the exterior of an existing window for sealing and insulating purposes. Exterior plastic film applied to the outside of a window, while providing a high degree of insulation, however, is neither very attractive nor durable. Further it does not allow the opening of the window in fair weather, and in effect, permanently seals the window.
There have also been interior insulating windows which generally consist of a transparent plastic panel or sheet held to the interior window frame by extruded plastic or other panel holding strips. See, for example, U.S. Pat. Nos. 3,939,620 and 4,069,641.
While many interior insulating windows are less expensive than the typical exterior aluminum storm windows, and generally more durable and attractive than film applied to the exterior, the interior type of insulating window consisting of a transparent plastic glazing panel secured to the window frame, may also result in a relatively permanently sealed window because such windows are not adapted to open and close occasionally during appropriate climactic conditions or seasonal weather changes, or for ventilation purposes.
Attempts have also been made to fabricate openable sashless plastic windows, such as the two track window described in U.S. Pat. No. 3,858,356. This type of window includes two separate panes, each in its own track, comprising a window which can be opened and closed by sliding the glazing panels up or down in their respective tracks. Such windows, however, are mounted within a separate box frame, and thus do not appear to be suitable for installation as an insulating window on an existing frame, but appear adapted to be used as replacements for prime windows.
Further, such windows include sashless panes riding in extruded finger strips. This requires a relatively critical fit of the panes with respect to the finger strips. If such strips are tight with respect to the pane, the pane may not slide well; friction and abrasion may wear the edges of the pane and the strips down. If the strips are loose, to allow the pane to slide easily, a poor air seal results, and a holding device may be necessary to hold an opened pane. Otherwise, it may be necessary to form the finger strips of teflon or silicone plastics, which are so expensive that the economic advantages of the designed extruded plastic window are defeated. In addition, a good seal of the strips against the casement is necessary to prevent air leakage or infiltration. And further, such types of windows do not allow the glazing panes to be easily removed for cleaning, replacement, or other maintenance. Hence, it is difficult in such windows to provide either optimium durability, insulation, or facility in use.
All such windows, if not particularly adapted for installation as "stock" sizes must further be either custom made or fitted to the size of a particular window. In view of the difficulties of these types of insulating windows, there has existed a need for a relatively inexpensive, attractive, durable and easily operated, openable extruded plastic window which is simply and easily fitted to accommodate to the pre-existing opening of a prime window.